Gabon court upholds Bongo poll victory, rejects opposition challenge

LIBREVILLE, Sept 23 (Reuters) - Gabon's Constitutional Court upheld on Friday the election victory of President Ali Bongo, whose family has ruled the central African oil producer for nearly a half century, rejecting a challenge by his main opponent.

The decision, read late at night in an almost empty court chamber, raised the prospect of a repeat of the violence that erupted with the announcement earlier this month of Bongo's narrow victory over Jean Ping in the Aug. 27 poll.

Six died in riots that caused major damage in the capital, Libreville, and elsewhere in the country of some 1.8 million people.

In a speech immediately after the court ruling, Bongo renewed a call for an open political dialogue to bring together both his allies and his opponents to work together in the country's best interest.

"When we come out of an election and families are having to mourn their dead, it means we've betrayed democracy," he told a crowd of supporters who minutes later erupted into a rendition of Gabon's national anthem.

There has been little indication that Ping, who has claimed he won the poll, is ready to enter talks with the government.

At the Libreville residence of the opposition leader - a former African Union Commission chairman - around a dozen of his supporters sat beside a swimming pool, watching in silence as a judge read the court's decision live on television.

"When the institutions of a country behave like this it is just sad," said one supporter, who gave his name only as Olivier. "Always it is the strongest who wins. The people's voice was rejected."

The government stepped up security in Libreville in the days leading up to the court ruling, deploying extra police and soldiers on the streets in an effort to head off trouble. The communications minister warned Ping on Wednesday that he risked arrest if violence broke out after the decision

In his petition to the court, Ping alleged fraud in Haut-Ogooue province, where Bongo won 95 percent on a turnout of 99.9 percent.

A European Union elections observer mission stated it had uncovered anomalies in the province's results.

The court refused to accept copies of vote tally sheets provided as evidence by Ping, many of which it said were illegible. Ping's legal team was absent from the courtroom as the ruling was announced.

Bongo's allies submitted evidence to the court rejecting Ping's allegations and countering that the opposition leader had himself orchestrated vote fraud.

The court cancelled results from 21 polling stations in Libreville over irregularities. The decision helped Bongo improve his margin of victory from 49.85 percent of ballots cast to 50.66 percent in the final court-certified result. (Additional reporting by Gerauds Wilfrieds Obangome in Libreville and Joe Bavier in Abidjan; Writing by Joe Bavier; Editing by Cynthia Osterman and Leslie Adler)